Papua New Guinea social campaigner, Noel Anjo, who said he saw the police taking action against the students outside the campus, predicted civil unrest in the wake of the shooting.

Mr Anjo said police had yelled abuse at the students and fired indiscriminately at them, resulting in chaotic scenes.

"There's civil unrest likely to take place. All the market places, all the shop... they're all closed, closing. And places are sending workers home and students are planning the next course of action and are gathering at the forum square now."

The students have been boycotting classes since the beginning of May, while demanding Prime Minister Peter O'Neill stand down to face corruption allegations.

Parliament, which was due to sit today, has been adjourned until August.